The speedometer cable is not that bad the second time you do it. The first time:
Feel behind the speedometer itself. Right where the cable plugs into the back of it. Around the outside there is a half circle shaped piece of metal. It sort of sticks out a little bit from the back of the speedometer. This is the release tab. It needs to be pushed it as far as you can push it towards the back of the speedometer. When it is pushed in, the whole cable can be pulled out the back.
Last one I removed, on my 72, I reached up from the bottom and pushed in the tab from under the dash. Had my son reach over the top of the dash and pull out the cable.
Easiest way on the EBrake for me was to loosen it up under the car first. However, I don't remember needing to take the EBrake loose to drop the dash.